A resin composition where, in order to improve the mechanical characteristics and the heat resistance of acryl resins such as polymethyl methacrylate (hereinafter, referred to as “PMMA”), inorganic fine particles are blended in a resin is known. As such resin composition, a resin composition where an acrylic polymer having an alkoxysilyl group and a metal alcolate are subjected to a sol-gel reaction to improve the mechanical characteristics is known (patent literature 1). Such the resin composition, when molded as optical members such as films or lenses, can be used as an optical member excellent in the mechanical characteristics.                [Patent literature 1] JP-A No. 2004-277512        